JP2007509811A - Pressure limiting device for a hydraulic brake circuit of a vehicle - Google Patents

Abstract

  The device comprises a liquid tight housing (1), which is fluidly connected between the braking elements of the front and rear wheels. This housing comprises means (2) and accessories, which allow hydraulic fluid to flow into the rear wheel braking element until an adjustable set pressure is reached, after which the set pressure is reached In response to an increase in pressure at the front wheel braking element, the pressure at the rear wheel braking element is reduced.

Description

  The present invention relates to the field of braking control circuits for all types of vehicles, in particular automobiles and motorcycles.

  As described above, the present invention has a particularly advantageous application with respect to a hydraulic braking circuit for a vehicle in which a force must be applied to an operating element such as a handle or a pedal in order to provide a pressure that can be applied to the braking element. But this type of use should not be considered totally limiting.

  The braking element, in particular the caliper, has a pad that is operated by a piston fluidly connected to the master cylinder, and the master cylinder can be moved by one or more operating elements that can be moved by hand or foot depending on the type of vehicle involved. Controlling is known to those skilled in the art. It is also known that braking action (which causes deceleration) causes a load shift to the front of the vehicle that leads to a load drop at the rear of the vehicle that can cause separation as seen in motorcycles.

  FIG. 1 shows an ideal theoretical braking equal adhesion curve as a function of the pressure applied to the front wheel or front wheel group (Y axis) relative to the pressure applied to the rear wheel or rear wheel group (X axis). This curve shows the following: That is, the pressure in the braking element of the rear wheel or the rear wheel group increases, and subsequently, the pressure is released in the braking element, so that the pressure gradually decreases.

  In fact, when the user uses the operating element, the pressure rises above the theoretical curve, causing one or more rear wheels to lock.

  In order to overcome this drawback, a pressure limiting device has been proposed for incorporation into the control circuit of the braking element of the rear wheel or rear wheel group. Its main function is to limit the pressure rise, but it does not gradually reduce the pressure. At best, these pressure limiting devices only allow this pressure to be maintained at a constant level on the plateau that appears at the highest value of the theoretical curve. In addition, these limiting devices are sensitive to the rate at which the pressure rises. Therefore, there is a significant variation from the set pressure depending on the pressure rise rate in the circuit.

  The object of the present invention is to overcome the above disadvantages simply, safely, effectively and reasonably.

  The problem to be solved by the present invention is firstly to suppress fluctuations in the speed at which the pressure increases, and secondly to reduce the pressure in the braking circuit of the rear wheel or rear wheel group of the vehicle. It is.

  In order to solve this problem, a pressure limiting device for a hydraulic brake circuit of a vehicle is fluidly connected between a braking element of a front wheel (or front wheel group) and a braking element of a rear wheel (or rear wheel group). A fluid-tight housing, which can allow hydraulic fluid to flow into the rear wheel braking element until an adjustable pressure is reached, and means for subsequently releasing this pressure; This mechanism is configured such that this pressure decreases at the rear wheel braking element as the pressure increases at the front wheel braking element.

  In order to solve the problem of gradually reducing the pressure in the braking element of the rear wheel or rear wheel group, the above means is a hollow cylinder having at each end a piston head that slides in a liquid-tight manner in the lumen of the housing. The cylinder, which allows free flow of fluid from the front wheel braking element to the rear wheel braking element and increases the pressure at the front wheel braking element in equilibrium when the set pressure is reached. Therefore, a mechanism for displacing the fluid to prevent the fluid from flowing into the braking element of the rear wheel is provided.

  In order to solve the problem of allowing free flow of hydraulic fluid by increasing pressure and reducing this pressure in the braking elements of the rear wheel from the set pressure, the mechanism in the cylinder is A coaxial bore opening in one piston head to which the hydraulic circuit of the wheel braking element is connected, the lumen receiving fluid from the braking element of the front wheel is in the lumen of the housing Loaded with a spring-controlled ball that cooperates with the coaxial finger of the liquid tight closure element fitted into the fluid, depending on the set pressure, or the fluid can flow freely, or the cylinder-piston assembly The whole of can be moved.

  Advantageously, fluid from the front wheel braking element is pumped into the housing lumen between the two piston heads forming a ring-shaped chamber, and between the end of the piston head and the closure element. In between, it is supplied to the braking elements of the rear wheels.

  To solve the problem with allowing free flow of fluid into the rear wheel braking element, when the ball abuts the finger on the face of the piston head located on the side of the closure element, A pin that can be seated on the closure element is arranged.

  In order to solve the problem of reducing the pressure in the braking element of the rear wheel as well as the problem of reducing this pressure, the cylinder-piston assembly is loaded into the lumen of the housing and the cylinder is used as an occlusion element. In contrast, the elastic element is controlled by an elastic element that can apply pressure to hold the fluid so that it can freely pass through, and prestress is applied to the elastic element to a value that matches the set pressure.

  In a preferred embodiment, the occlusion element is provided within the housing lumen to allow adjustment of its translational movement to allow adjustment of prestress on the elastic element, thereby concomitantly changing the set pressure. It has come to be.

  In view of the issues to be addressed, in a preferred embodiment, the piston head cooperating with the prestressed elastic element has a larger diameter than the other head, and the housing lumen corresponds differently. Two coaxial internal receivers of diameter are formed.

  Variations of the basic design are also conceivable.

  For example, in one embodiment, a piston head cooperating with a prestressed elastic element has a smaller diameter than that of another head, and the housing lumen has two correspondingly different diameters. Two coaxial inner bearings are formed.

  In another embodiment, the piston head cooperating with the prestressed elastic element has the same diameter as that of the other head, and the housing bore is formed with an internal receiver of the corresponding diameter. Is done.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  The pressure limiting device according to the invention comprises a small liquid-tight housing (1) that can be incorporated into or added to a hydraulic circuit configured to control a braking element. As can be seen from FIG. 5, this pressure limiting device is fluidly connected between the braking element (F1) of the front wheel or front wheel group (AV) and the braking element (F2) of the rear wheel or rear wheel group (AR). Connected. In a standard manner well known to those skilled in the art, the braking elements (F1) and (F2) may be pedals, steering wheels, or others, depending on the type of vehicle to be equipped. Controlled by a master cylinder (C) operated by an operating element (O).

  The housing (1) constitutes a compact, independent assembly formed in a generally rectangular box shape. The wall of the housing (1) includes channels (1a) and (1b) connected to connection receptacles (1a1), (1b1) for connection with a hydraulic braking circuit. This connection can be realized using a hose, for example. The channel (1a) is connected to the hydraulic circuit of the braking element (F1) of the front wheel or front wheel group (AV), while the channel (1b) is the fluid of the braking element (F2) of the rear wheel or rear wheel group (AR). Connected to the pressure circuit. The channels (1a) and (1b) are connected to a lumen (1c) coaxial with the housing (1). Obviously, the housing (1) has means (1d) and (1e) for allowing it to be fixed to a part of the relevant vehicle by screws or other means.

  According to one aspect of the present invention, the lumen (1c) of the housing (1) accommodates a hollow cylindrical body (2) that slides in the lumen in a liquid-tight state. This cylindrical body (2) has piston heads (2a) and (2b) at both ends. Importantly, as will be explained later, the cylinder-piston assembly (2) is provided by a prestressed spring (3) disposed at the bottom of the elastic element, ie the lumen (1c). Be controlled.

  The cylindrical body (2) is in a coaxial shaft that opens to the piston head (2b) on the side of the channel (1b) connected to the hydraulic circuit of the braking element (F2) of the rear wheel or rear wheel group (AR). A cavity (2c) is provided. The fluid sent from the braking element (F1) of the front wheel or the front wheel group (AV) flows into the lumen (2c) through the hole (2d). The lumen (2c) houses a ball (4) arranged at the bottom thereof, controlled by a spring (5). This ball (4) cooperates with the coaxial finger (6a) of the liquid tight closure element (6) fitted on the side of the through hole of the lumen (1c).

  When the ball (4) abuts the finger (6a), it leaves its seat (2e) and freely passes through the channel (1a), the lumen (2c) and the channel (1b) to allow hydraulic fluid to freely Allows to flow. Conversely, when the ball (4) is no longer in contact with the finger (6a), the ball (4) is pushed toward the bottom of its seat (2e) by the spring (5) and will be described further below. As such, it results in the closure of the circuit for the braking element of the rear wheel or rear wheel group (AR).

  For this purpose, fluid from the braking element of the front wheel or front wheel group (AV) is in the housing (1) between the two piston heads (2a) and (2b), forming a ring-shaped chamber. Into the cavity (1c). The spring (3) to which the prestress is applied depending on the selected set pressure value is such that the piston head (2b) of the cylindrical body (2) is moved against the closing element (6) with respect to the piston head (2a). Apply pressing force.

  In this position (FIG. 6), the ball (4) is in contact with the finger (6a) of the closure element (6) away from its seat (2c), so that the fluid flows into the channel ( It can flow freely through 1a), lumen (2c) and channel (1b). The surface of the piston head (2b) can be seated on the head (6b) of the closure element (6) when the ball (4) is in contact with the finger (6a) to allow free passage of hydraulic fluid. Note that a pin (2b1) is provided.

  Here, the operation of the pressure limiting device of the present invention will be described. When the pressure (P1) applied to the braking element of the front wheel or front wheel group increases and exceeds a preselected setting value, that is, the prestress value of the spring (3), the cylindrical body (2) moves backward and the spring ( 3) is compressed (FIG. 7). The ball (4) is no longer held by the finger (6a), it is pushed by the spring (5) and moves to close the seat (2e). In this position (FIG. 7), the pressure (P2) applied to the braking element (F2) of the rear wheel or rear wheel group (AR) decreases as the pressure increases in the braking element of the front wheel or front wheel group.

  In a preferred embodiment of the invention based on the above design, the piston head (2a) has a larger diameter than the other head (2b). In this configuration, the housing lumen (1c) forms two internal receptacles (1c1) and (1c2). The inner receptacles (1c1) and (1c2) are arranged coaxially and have different diameters that match those of the piston. According to this embodiment, a curve (FIG. 2) that approximates a theoretical equal adhesion curve is obtained. This initially follows the pressure rise of the fluid normally flowing through the pressure limiting device via the channel (1a), the housing (2c) and the channel (1b). Thereafter, when the set pressure is reached, as the pressure increases in the braking element of the front wheel or front wheel group, the pressure in the braking element of the rear wheel or rear wheel group decreases.

  When the diameter of the piston head (2a) is smaller than that of the piston head (2b), a curve as shown in FIG. 3 is obtained.

  Finally, when the diameter of the piston head (2a) is the same as that of the piston head (2b), a curve as shown in FIG. 4 is obtained.

  Clearly, in this configuration, the housing lumen (1c) forms an internal receptacle that is of equal diameter along its entire length.

  Advantageously, the occlusion element (6) is arranged in the housing so that its translational movement can be adjusted in order to be able to adjust the prestress on the spring (3), which concomitantly changes the set pressure. It is inserted into the cavity (1c). For example, the occlusive element (6) consists of a cylindrical body having a threaded receiving surface (6c) that can be screwed onto the inner screw (1f) at the entrance of the lumen (1c). This cylindrical body (6) can be operated using the finger wheel (6d).

  The advantages of the present invention are apparent from the above description. Of particular importance, the pressure limiting device of the present invention suppresses fluctuations in the rate at which the pressure rises and allows this pressure to be reduced in the rear wheel braking element circuit as a function of a preselected set pressure. It is a fact that.

It is a graph which shows the theoretical equal adhesion curve of ideal braking. It is a graph which shows the curve obtained by the pressure limiting device in comparison with the ideal curve (shown by a broken line) in FIG. It is a graph which shows the curve obtained by the pressure limiting device in comparison with the ideal curve (shown by a broken line) in FIG. It is a graph which shows the curve obtained by the pressure limiting device in comparison with the ideal curve (shown by a broken line) in FIG. 1 is a schematic diagram showing an assembly of a pressure limiting device in a hydraulic brake circuit of a vehicle. FIG. 2 is a longitudinal cross-sectional view of the restriction device in a position where fluid can flow, in which state the pressure applied to the rear wheel braking element is below a selected set pressure. FIG. 7 is a view similar to FIG. 6. In this state, the pressure applied to the rear wheel braking element exceeds the selected set pressure.

Explanation of symbols

AV front wheel (or front wheel group)
AR Rear wheel (or rear wheel group)
C Master cylinder F1, F2 Braking element O Operating element 1 Housing 1a, 1b Channel 1a1, 1b1 Connection receiving part 1c Lumen 1c1, 1c2 Internal receiving part 1d, 1e Means for fixing 1f Internal screw 2 Cylindrical body 2a, 2b Piston Head 2b1 Pin 2c Coaxial lumen 2d Hole 2e Seat 3 Spring 4 Ball 5 Spring 6 Liquid tight closure element 6a Coaxial finger 6b Head 6c Threaded receiving surface 6d Finger wheel

Claims (10)

A pressure limiting device for a hydraulic brake circuit of a vehicle,
A fluid-tight housing (1) fluidly connected between the front wheel braking element and the rear wheel braking element;
The housing (1) comprises means (2) and a mechanism that allows hydraulic fluid to flow into the rear wheel braking element until an adjustable set pressure is reached and subsequently relieve this pressure. Thus, the pressure limiting device is characterized in that as the pressure increases in the braking element of the front wheel, the pressure decreases in the braking element of the rear wheel. The means comprises a hollow cylindrical body (2) having piston heads (2a) and (2b) which slide in a liquid-tight state in the lumen (1c) of the housing (1) at each end,
The cylinder (2) allows free flow of fluid from the front wheel braking element to the rear wheel braking element and when a set pressure is reached, fluid flows into the rear wheel braking element. The device according to claim 1, further comprising a mechanism for displacing the cylindrical body (2) so as to prevent the phenomenon.   The mechanism of the cylindrical body (2) comprises a coaxial lumen (2c) that opens to one (2b) of the piston head on the side to which the hydraulic circuit of the braking element of the rear wheel is connected. A coaxial finger (6a) of a fluid tight closure element (6) fitted in the lumen (1c) of the housing (1) is received in the lumen (2c) for receiving fluid from the braking element of the front wheel. Is loaded with a ball (4) controlled by a spring (5) which cooperates with the fluid, depending on the set pressure, the fluid can flow freely or the entire cylinder-piston assembly (2) moves The device according to claim 1, wherein the device is configured to be able to do this.   Fluid from the braking element of the front wheel is fed into the lumen (1c) of the housing (1) between the two piston heads (2a) and (2b) forming a ring-shaped chamber, and the piston 3. Device according to claim 2, characterized in that it is sent to the braking element of the rear wheel between the end of the head (2b) and the closure element (6).   A pin (2b1) is disposed on the surface of the piston head (2b) located on the side of the closing element (6), and the pin (2b1) is configured to allow the fluid to flow freely. 5. The device according to claim 1, wherein when the ball (4) abuts on the finger (6 a), the ball (4) can be seated on the closing element (6). apparatus.   The cylinder-piston assembly (2) is provided in the lumen (1c) of the housing (1) and displaces the cylinder (2) to the closure element (6) to allow free fluid flow. The elastic element (3) is controlled by an elastic element (3) capable of applying pressure to hold the pre-stress to a value commensurate with the set pressure. The apparatus according to any one of claims 1 to 5.   The closure element (6) is provided in the lumen (1c) of the housing (1) so that its translational movement can be adjusted in order to allow adjustment of the prestress on the elastic element (3). 7. The device according to claim 1, wherein the set pressure is changed incidentally.   The piston head (2a) cooperating with the prestressed elastic element (3) has a larger diameter than the other head (2b), and the lumen (1c) of the housing 8. A device according to claim 1, wherein two coaxial inner receptacles (1c1)-(1c2) of different corresponding diameters are formed.   The piston head (2a) cooperating with the prestressed elastic element (3) has a smaller diameter than the other head (2b), and the lumen (1c) of the housing (1) 8. The device according to claim 1, wherein two coaxial inner receptacles (1c1)-(1c2) of different corresponding diameters are formed. The piston head (2a) cooperating with the prestressed elastic element has the same diameter as the other head (2b), and corresponds to the lumen (1c) of the housing (1). 2. The device according to claim 1, wherein an inner receiving portion having a diameter is formed.

Images